It is a cliche to observe that no time in human history has seen so much change, so rapidly, but it certainly applies to attitudes to homosexuality within my lifetime.

When I was born, in 1949, men and women led secret sex lives, and lived in fear of arrest and imprisonment.

But in time gay people started to emerge from these semi-criminal shadows; the world was changing and homosexual love, which is as old as humanity itself, began to become part of normal life.

When I was 18, gay people older than 21 were at last allowed to have sex legally. I, at 18, was still illegal, but things were on the move. Up to a point.

Gay couples were still denied the basic legal provisions extended both to married people and to common-law spouses.

Then came the astonishing breakthrough of civil partnership - a huge leap forward - marriage in all but name.

But, in a very important sense, the name of marriage is what marriage is.

A symbolic commitment, a huge step in a relationship, an ideal and a blessing, something beyond a legal contract. Something instinct with meaning. And this is what many gay people want for themselves.

If David Cameron's Big Society means anything, it means, not just inclusiveness, but mutual respect and - the guarantee of that respect - shared institutions, so we all participate equally in our country's life.

The prime minister has with commendable boldness and clarity expressed himself in favour of gay marriage; it is said that he plans to fast-track the appropriate legislation.

There are those in his party who resist this change, as they have resisted every significant social change, harking back to a golden age.

Golden for some few perhaps, but the dark ages for many others - the poor, women, people from other races, and gay people.

I deeply love my partner, for better or for worse, for richer, for poorer, in sickness and in health, to love and to cherish; from this day forward until death do us part.

The change in the law will set its seal on our love; and ensure that we will be fully part of the institutions of our society.

There are gay people who rejoice in their separateness from society, seeing their sexuality as a form of rebellion, a protest, even as something superior to heterosexual desire.

I have never been of that persuasion; I see my sexuality as perfectly normal and indeed ordinary.

It has suited society to infantilise homosexuality, to see gays as amusing children or fecklessly promiscuous, trapped in a sort of permanent adolescence.

The availability of marriage to gay people seems to me a step towards something much more grown up.